The use of blow-molding as a method for manufacturing various sorts of articles is generally well know. Typically, this process involves the use of a mold consisting of two separate halves or portions having cavities of particularly desired shapes and sizes. Usually, one extrudes a large-diameter, sealed tube of molten material (commonly referred to as a “parison”), places the tube between the mold halves, and closes the mold around the tube. Fluid pressure is then introduced into the tube, forcing the molten tube against the walls of the cavities, conforming the tube to the shape thereof. The pressure is maintained until the molten material cools and solidifies. The pressure is then released, the mold halves are pulled apart, and the hardened article is ejected therefrom.
One such article that is commonly manufactured in this manner is pouring containers. In many blow molded containers, and particularly in pouring containers, it is desired or necessary to create holes in the container. However, because the blow molding process involves the use of a parison with a continuous, unbroken surface, the mold itself cannot form any holes other than the hole through which the fluid pressure is introduced. Cutting these holes after the blow molding process is completed and the container has been ejected from the mold, however, requires additional tooling and additional manufacturing steps, entailing further difficulty, time, and expense. Moreover, because the hole is often in a location that is difficult to access with the cutter, defects in the quality of the cut often result.
Accordingly, various methods and devices have been suggested to create these holes in blow molded articles during the blow molding process, such as that disclosed in disclosed in U.S. Patent Application No. US 2003/0104098 in the name of Schrader, which is incorporated herein by reference. However, one problem that arises in the case of pouring containers is that it is typically desired to produce the container with a handle. Therefore, the mold must have a section with a cavity for creating the reservoir (or body) portion of the container and a section with a cavity for creating the handle of the container. Usually, of course, it is desired to have a large fill hole at the top of the reservoir portion, both for convenience and in order to allow the reservoir section of the container to be filled to maximum capacity. However, this hole is under the handle, and thus, the handle section of the mold blocks the path of any punch that would otherwise be used to create the fill hole.
Additionally, one type of pouring container for which the blow molding process is particularly well suited is watering cans. A watering can typically has a spout with a frusto-conical end (commonly called a “rose”), flaring out to a wide surface having many small holes, through which the water exits the can. In order to create these many small holes, the rose is manufactured as a separate part and then assembled onto the blow molded container.
One disadvantage of creating the rose as a separate part, however, is that it requires additional steps in the manufacturing process, resulting in increased time and expense. Moreover, the end of spout must be threaded in order to permit the rose to be screwed on, which results in significant additional tooling, and thus, additional costs. Another disadvantage of a separate rose part that is screwed on to the spout is that it presents the possibility of leakage through and/or irregular flow over the joint between the rose and spout. Finally, yet another disadvantage of a separate rose part is that the rose often becomes separated from the watering can and subsequently lost, either while in transit, or in a store or the ultimate purchaser's home, thereby rendering the entire watering can virtually useless.
What is desired, therefore, is a method and apparatus that facilitates the creation of holes in a blow molded pouring container that does not require additional tooling or manufacturing steps and does not require the production of separate container parts.